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Show 34 GEOLOGY OF THE HIGH PLATEAUS. south of Salina. Resuming its northerly trend, the fault with a reversed throw passes along the west side of Gunnison Valley with a shear of at least 3,000 feet, and runs obliquely up on the great Wasatch Monoclinal, forming a superimposed displacement, and then cuts obliquely down into San Pete Valley, where it disappears. It may continue farther northward, but it has not been traced in that direction beyond San Pete Valley. Its total observed length is very nearly 100 miles. It is everywhere a true fault, though at several places it is complicated by minor fractures and some flexing of the thrown beds. I have not included the East Musinia fault among the greater displacements, though it has considerable lengthâ€"perhaps 45 milesâ€"and at one place in Gunnison Valley the shear reaches more than 2,000 feet, and possibly near to 3,000 feet. It is, however, an important feature, and almost entitled to rank with the greater faults of the system. It is parallel to the northern portion of the Thousand Lake fault last described, and might be called a mate to it, since the two hold between them the sunken block of Gunnison Valley and the continuation of that block obliquely across the great Wasatch Monoclinal. This sunken block is an interesting occurrence, and belongs to that kind of complicated fracture which Powell has named "Zone of Diverse Displacement." The part of it which lies in the lowest portion of Gunnison Valley has been analyzed and described by Mr. Gilbert. It extends both north and south from this locality, and in the former direction continues to display the same comminuted fracture in great variety for a distance of more than 20 miles, while the width of the zone does not exceed 3 miles. It appears to be a very clear case of a block dropping through the drawing apart of the strata and sinking to fill the gap thus produced. Another instance occurs along the western base of the Aquarius Plateau in the southernmost portion of Grass Valley. Here the block between the faults, instead of shearing sharply on both sides, has partly careened and settled down synclinally. These displacements do not belong wholly to any one period. There is evidence that different faults belong to different agesâ€"not widely separated probably, but recognizably distinct. There is evidence that different |